Calibrating a laptop battery can increase or restore its efficiency. This should be done prior to first use, and again when you notice battery efficiency decreasing. Calibrating a battery experiencing decreased efficiency is most effective on nickel-cadmium (NiCad) and nickel-metal hydride (NiMH) batteries. You can still calibrate a lithium ion (Li-ion) battery, though the process is a bit different. Calibrating involves draining and recharging the battery. This process is also referred to as conditioning.
